With nearly one-third of all children in the U.S. considered overweight, finding clothing that fits has become a challenge for overweight kids.

According to a new report from The NPD Group, mothers of overweight children reported 31 percent of their nine to twelve-year-old boys and 38 percent of girls in this age group are already wearing mens, womens or junior-size apparel.

The overweight nine- to twelve-year-old boy and girl appear to be stuck between youth sizing that is too small and adult sizing that is larger, but not proportional.

According to the report, 74 percent of overweight boys and 84 percent of overweight girls in the nine to twelve-year-old age group are "sizing up" to buy sizes other than those typically made for children their age.

NPD found that pants are the hardest clothing item to buy for overweight children. Moving up to adult sizes often means jeans fit too long for boys and are ill-proportioned in the hips, waist or legs for girls.

What Are Mothers Saying?

According to the report, overweight boys are twice as likely to wear mens-sized apparel, compared with total boys ages nine to twelve. One mother said she has a difficult time finding "clothes like some of his friends" when shopping for her ten-year-old son.

"When kids have to size up to mens and womens sizes it can be challenging to find clothes that are age-appropriate," said Marshal Cohen, chief industry analyst, The NPD Group.

Over eight in ten mothers of overweight girls ages nine to twelve said "the choice of clothing styles that fit my daughter is limited;" almost as many (79%) agreed that "I cant find the stylish clothes my child wants in sizes that fit." One mother stated "clothing is too risqu" for her 12-year-old daughter.

Mothers Misperceive Childrens Weight

Although the Centers for Disease Control (CDC) estimates 30 percent of children in the U.S. are technically overweight based on height and weight calculations of Body Mass Index (BMI), only 13 percent of moms say they consider their kids overweight.

When calculations were done based on the childs height and weight, the number of overweight kids is much closer to the CDC estimates -- a whopping 34 percent.

"While plus-size women and big and tall men are willing to shop at separate stores or special sizing racks, mothers dont want to shop that way for their children, especially if they see their child as average when it comes to size," said Cohen. "More importantly, they will want the same styles and brands that they see other moms shopping for, so their children can fit in with their peers."

"Kids, like adults, often have special size needs. Moving into bigger sizes is only part of the solution. The challenge for retailers and brands will be to recognize that there are significant differences in communicating and connecting with adults and childrens special size needs. If retailers address this issue then capturing just a small percentage of this group will generate some significant growth in revenue," said Cohen.